Needle retraction mechanisms

ABSTRACT

A fluid handling device has a needle retraction assembly which brings about the retraction of a hollow needle after use. A hollow body portion is provided at one end, with an end wall having a mounting portion including a needle passage. A hollow needle having a leading end portion is movable between a first position in which the leading end portion of the needle protrudes from a front end portion of said mounting portion and a second position in which the needle is withdrawn within the hollow body portion. A spring acts to bias the needle into the second, withdrawn position. The needle is provided with a portion of enlarged diameter at a location spaced from the leading end portion. A retainer maintains the needle in its first position until use is completed. The retainer includes an O-ring positioned in a circumferential groove in the portion of enlarged diameter. The O-ring abuts the end of a sleeve slidable within the mounting portion and which can be forced forwardly to dislodge the O-ring so as to permit the needle to move from its first position into its second position under the influence of the spring.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention is concerned with improvements in or relating toretraction mechanisms for use in fluid handling devices, said mechanismsbeing arranged to bring about the retraction of a hollow needle into ahousing after use. Such devices are used in many facets of the medicalfield, for the administration of drugs or a drip feed into a bloodvessel, or for drawing off liquid samples, for example, blood frompatients.

2. Description of the Related Art

It will be understood that there is a wide range of fluid handlingdevices incorporating needles in use in the field of medicine for theadministration of drugs and the like for blood sampling, including usein procuring more than one sample from a patient over a period of time.

It is important that the needles of such devices, which are frequentlyintended for disposal after a single use, are rendered inoperative toprevent accidental injury or re-use with the substantial risk ofcross-contamination.

Syringes provided with guards of one kind or another which areautomatically deployed to shield the needle after use are known, as aresyringes where the needle is automatically retracted after use into thebody of the device.

The invention provides a fluid handling device having a needleretraction assembly adapted to bring about the retraction of a hollowneedle after use comprising a hollow body portion provided at one endthereof with an end wall having a mounting portion including a needlepassage, and a hollow needle having a mounting means and adapted to bemovable between a first position in which a leading end portion of theneedle protrudes from a front end portion of said mounting portion and asecond position in which the needle is withdrawn within the hollow bodyportion, said mounting means including resilient means that act to biasthe needle into the second, withdrawn, position, said needle beingprovided with an enlarged portion at a location spaced from the leadingend portion thereof, there being provided retaining means to maintainthe needle in its first position until use is completed, said retainingmeans comprising in combination an O-ring positioned in acircumferential groove in said enlarged portion and abutting the end ofa sleeve which can be forced forwardly to dislodge the O-ring so as topermit the needle to move from its first position into its secondposition under the influence of said resilient means.

The sleeve may be restrained from rearward movement when the needle isin its first position by a shoulder which abuts a flange at the forwardend of the body portion.

The resilient means may be a compression spring located between aforward reaction surface provided by the mounting portion and a rearwardreaction surface provided by the forward end of the enlarged portion.

When the needle is in its first position the O-ring may be compressedbetween the enlarged portion and the mounting portion, which provides arelieved part at its forward end to receive the O-ring when it isdislodged.

The fluid handling device may be a syringe, there being a piston whichmay be depressed to travel through the body portion to discharge liquidtherefrom through the needle, the piston being in the form of a tubehaving closed ends, the forward of which is provided with a closuremember which is separable from the end by engagement with the sleeve asthe piston is fully depressed to provide an aperture in the end throughwhich the needle may pass to enter the interior of the piston as itassumes its second position.

The mounting portion may be off-centre and towards a peripheral edge ofthe body portion.

The cross-sections of the body portion and piston may be such as toprohibit incorrect assembly having regard to the position of the closuremember.

The cross-sections of the body portion and piston may be such thatwhilst permitting assembly in more than one rotational position relativeto one another, proper operation is assured, there being more than oneclosure member in the end of the piston.

The body portion and piston may be of elliptical section, there beingtwo spaced closure members in the end of the piston.

The hollow body portion may not be intended to receive a piston, and apiston-like tool may be inserted into the body portion to causeretraction of the needle into the tool when desired.

The sleeve may be located in a recess accessible by a portion of reducedsize on the forward end of the tool adapted to enter the recess toengage with the sleeve. This prevents premature retraction of theneedle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a syringe according to the invention, in anunused condition;

FIG. 2 is a longitudinal section of the syringe taken on line II--II ofFIG. 1 and to an enlarged scale;

FIG. 3 is an end view of the syringe;

FIG. 4 is a section on lines IV--IV of FIG. 2;

FIG. 5 is an opposite end view, being a needle end view;

FIG. 6 is a sectional view similar to FIG. 1 illustrating anintermediate stage in the depression of a plunger of the syringe;

FIG. 7 is a similar view illustrating the completion of the depressionstep;

FIGS. 8, 9 and 10 are fragmentary views to an enlarged scale of portionsof FIGS. 2, 6 and 7 respectively;

FIG. 11 is a fragmentary longitudinal sectional view of a fluid handlingdevice for taking blood samples;

FIG. 12 is a similar view with a needle retraction tool insertedtherein; and

FIG. 13 is a view of the device with the needle thereof in a retractedcondition.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A disposable syringe 2 is shown in FIG. 1 comprising a hollow bodyportion 4, from the rear of which (upper end as viewed in FIG. 1)protrudes a piston 6. At the lower end of the body portion 4 is provideda mounting portion 8 for a needle 10, having a through passage at theinner end of which is an upstanding annular wall 9.

The hollow body portion 4, which is non-opaque, is graduated inmillilitres for convenience and is provided with finger-engaging flanges12 in the conventional manner. The body portion 4 has a slightlyoutwardly flared end portion 15. The mounting portion 8 is secured to anend wall 14 of the body portion 4 in an off-centre position at 16 (seeFIG. 2) to facilitate use of the syringe in enabling the needle 10 topenetrate tissue or a blood vessel at as shallow an angle as desired.

The inner end of the needle 10 connects with a collar 18 having anannular groove 19 in which is received an O-ring 20. Groove 19 providesa shoulder against which the O-ring 20 abuts. The collar 18 is bonded tothe needle so as to be integral therewith.

As best seen from FIGS. 3 to 5 the body portion 4 and piston 6 are ofelliptical section which avoids any tendency for unwanted relativerotation of the parts.

The mounting portion 8 provides a passageway for the needle 10 andprovides a first reaction surface 26 for a compression spring 28surrounding the needle. A second reaction surface 30 is provided on aforward end of the collar 18. When assembled the spring 28 is in analmost fully compressed condition between the surfaces 26 and 30 and ismaintained in that condition by engagement of the O-ring 20, which iscompressed between an annular wall portion 32 of the mounting part 8 andits groove 19, with an end surface 34 of a sleeve 36 surrounding thecollar 18 and comprising at its rearward end an extension 38, formed bylugs, which project into the hollow body portion 4 in the pre-usecondition shown in FIGS. 2 and 8.

As may be seen in FIG. 8, an annular space 35 is provided to the forwardside of O-ring 20.

The sleeve 36 has a shoulder 37 which engages an annular flange 39 atthe forward end of the body 4 to prevent rearward movement of the sleeve36 from its initial position shown in FIGS. 2 and 8.

The piston 6 is hollow having its rear end closed by means of a cap 40.It will be noticed that the diameter of the piston is greatest at therear end of the piston at 13, that is, adjacent the end cap 40 andtapers inwardly towards the body portion.

The other end of the piston is arranged to receive a closure member 42which engages firmly in the piston to form an end wall having two areas44 defined by lines of weakness 46 so as to be readily removed oncontact with the sleeve extension lugs 38 in a manner to be explainedbelow. The provision of two such areas 44 obviates the need to check theposition of the off-set needle 10 during assembly.

In operation, the syringe is conveniently charged with liquid in anormal manner, to achieve its ready-for-use condition in which thepiston 6 is received within the body portion 4 by a short distance asshown in FIG. 2. The closure member 42 of the piston thus also acts as aseal for the liquid contents of the body portion.

On actuation of the piston 6 so as to move forwardly (or downwardly asviewed in the FIG. 1), the advance of the end wall of the member 42expels the liquid through the needle 10. FIG. 9 shows the position ofthe parts immediately before the expulsion of the liquid is completed.It will be observed that the end wall of the member 42 has contacted thelugs 38 of the sleeve member 36 and has forced the member 36 forwardlyas shown in FIGS. 9. However, liquid may still pass from the bodyportion 4 to the needle 10 due to the spaces between the lugs 38 of thesleeve 36. In FIG. 10, the movement of the sleeve member 36, because ofits contact with the O-ring 20 that is received in the groove 19, hascaused the collar 18 also to move forwardly, further compressing thespring 28 to a fully compressed state. In addition, this movement causesthe O-ring 20 to be released from entrapment in the groove 19 by theannular portion 32 and to be dislodged from the shoulder to enter theannular space 35, where it is received over the wall 9 of the mountingportion 8. Thus the restraint acting upon the needle end portion 18 isremoved. The fully compressed spring 28 is now no longer constrained andextends rapidly, propelling the needle end portion 18 and therefore alsothe needle itself rearwardly. The sleeve member 36 and its lugs 38 aretogether of such a length as still to project into the hollow interiorof the body portion 4. The lugs therefore provide a pressure areaagainst the area 44 so as to shear the line of weakness 46. The needle10 is thus free to pass through the sleeve member 36 into the hollowinterior of the piston 6, so that the needle is withdrawn from access bypotential re-users of the syringe. It will be understood that the piston6 cannot in practice readily be withdrawn from the body portion 4 tofacilitate access to the needle, since the annular portion 13 of thepiston 6 is firmly wedged into the flared end portion 15 of the bodyportion 4 and thus resists removal.

The syringe may therefore now be disposed of without risk to personssubsequently handling the needle.

FIG. 11 shows a fragmentary view of a needle retraction mechanismindicated at 48, for use in a device for taking repeated blood samples.The device comprises an open-ended housing 50 into which is inserted anevacuated tube 52 of the kind sold under the Registered Trade Mark"Vacutainer", having a diaphragm 54 which is pierced by a rear endportion 56 of a double-ended hollow needle 58 so that the sample may bedrawn into the tube 52. Conveniently, the needle 58 may remain in placeduring the period of time in which it may be necessary to take a seriesof samples, but when the series is completed, the needle must be removedand the risks associated with used needles then arise.

The needle retraction mechanism of the device of FIGS. 11 to 13 issimilar in many respects to that shown in the syringe of FIGS. 1 to 10,like parts being indicated by like reference numerals.

The needle 58 which as mentioned above is double-ended and passesthrough the collar 18.

A recessed portion 82 is formed in the forward wall of the housing 50which has a surface 86 against which the evacuated tube 52 abuts innormal use. Thus in normal use, it will be observed, no contact is madeby the tube 52 with the lugs 38.

FIG. 12 illustrates the means by which the needle 58 may be retractedout of an operative condition and into a position which it cannot beused again nor can it injure anyone handling it.

Thus when the final sample has been taken and the needle of the deviceneeds to be removed from the patient's arm, a tool 88 is inserted intothe housing 50 as shown in FIG. 12. The tool 88 comprises plunger-likehollow body portion 90 and an annular projection or neck 92 that issurrounded by a shoulder surface 94. The neck 92 has a circular opening96. As the tool 88 is inserted into the housing 50, the needle endportion 56 enters the opening 96 in the neck 92 and the neck itselfenters the recess 82 in the housing 50. The leading edge surface of theneck 92 contacts the lugs 38 and continued pressure applied to move thetool forwardly as shown in FIG. 12 causes the sleeve member 36 to moveforwardly to dislodge the O-ring 20 to release the needle 58 fordischarge into the body of the tool 88. A snap-on ring clip 98 aroundthe tool 88 ensures that the tool is not accidentally removed from thehousing 50 before safe disposal.

Various modifications may be made within the scope of the invention asdefined by the following claims.

I claim:
 1. A fluid handling device having a needle retraction assemblyadapted to bring about the retraction of a hollow needle after use, saidfluid handling device comprising:a hollow body portion provided at oneend thereof with an end wall having a hollow mounting portion, saidmounting portion comprising an annular wall extending distally from saidend wall, said mounting portion further including a distal wall having aneedle passage therethrough; a hollow needle having a tissue penetratingend portion and being adapted to be movable between a first position inwhich the tissue penetrating end portion of the needle protrudes fromsaid needle passage of said hollow mounting portion and a secondposition in which the needle is withdrawn completely within the hollowbody portion, said needle being provided with a collar portion ofenlarged diameter at a location spaced from the tissue penetrating endportion thereof, and being located within said hollow mounting portion;an O-ring positioned against a circumferential shoulder on said collarportion of enlarged diameter and said annular wall of said mountingportion for providing a fluid seal therebetween as well as for retainingthe needle in its first position until use is completed; a springlocated between said distal wall of said mounting portion and a distalend of said collar portion of enlarged diameter, said spring for biasingsaid needle into the second position within said hollow body portion;and a sleeve located around said collar portion of enlarged diameter andwithin the hollow mounting portion of said hollow body portion, saidsleeve having a distal end in contact with said O-ring, said sleevebeing slidable within the mounting portion and which can be forcedforwardly to dislodge the O-ring from said shoulder so as to permit theneedle to move automatically from its first position into its secondposition under the influence of said spring.
 2. The fluid handlingdevice according to claim 1, wherein said device is a syringe, saidsyringe having a hollow piston within said body portion which may bedepressed to travel through said body portion to discharge liquidtherefrom through the needle, the piston being in the form of a tubehaving closed ends, the forward of which is provided with a closuremember which is separable from the end by engagement with said sleeve asthe piston is fully depressed to provide an aperture in the forward endthrough which the needle may pass to enter the interior of the piston asit assumes its second position.
 3. The fluid handling device accordingto claim 2 wherein the mounting portion is off-center and towards aperipheral edge of the body portion.
 4. The fluid handling deviceaccording to claim 3, wherein the cross-sections of the body portion andpiston are such as to prohibit assembly with the closure member offsetfrom the needle.
 5. The fluid handling device according to claim 1wherein a hollow tool may be insertable into the body portion to slidethe sleeve forwardly to cause dislodge said O-ring to retraction of theneedle into the tool when desired.
 6. The fluid handling deviceaccording to claim 5 wherein a proximal end of said sleeve is located ina recess within said end wall of said hollow body accessible by aportion of reduced size on the forward end of the tool said proximal endof said sleeve adapted to enter said recess to engage with said sleeve.7. The fluid handling device according to claim 1, wherein said mountingportion has an area of enlarged internal diameter at its forward end toreceive the O-ring when it is dislodged.
 8. A fluid handling devicehaving a needle retraction assembly adapted to bring about theretraction of a hollow needle after use, said fluid handling devicecomprising:a hollow body portion provided at one end thereof with an endwall having a hollow mounting portion, said mounting portion comprisingan annular wall extending distally from said end wall, said mountingportion further including a distal wall having a needle passagetherethrough; a hollow needle having a tissue penetrating end portionand being adapted to be movable between a first position in which thetissue penetrating end portion of the needle protrudes from said needlepassage of said hollow mounting portion and a second position in whichthe needle is withdrawn completely within the hollow body portion, saidneedle being provided with a collar portion of enlarged diameter at alocation spaced from the tissue penetrating end portion thereof, andbeing located within said hollow mounting portion; an O-ring positionedagainst a circumferential shoulder on said collar portion of enlargeddiameter and said annular wall of said mounting portion for providing afluid seal therebetween as well as for retaining the needle in its firstposition until use is completed; a spring located between said distalwall of said mounting portion and a distal end of said collar portion ofenlarged diameter, said spring for biasing said needle into the secondposition within said hollow body portion; and a sleeve located aroundsaid collar portion of enlarged diameter and within the hollow mountingportion of said hollow body portion, said sleeve having a distal end incontact with said O-ring, said sleeve being slidable within the mountingportion and which can be forced forwardly to dislodge the O-ring fromsaid shoulder so as to permit the needle to move automatically from itsfirst position into its second position under the influence of saidspring, wherein said sleeve is restrained from rearward movement whenthe needle is in its first position by a shoulder on said sleeve whichabuts a flange on said annular wall of said mounting portion.
 9. Thefluid handling device according to claim 8, wherein said device is asyringe, said syringe having a hollow piston within said body portionwhich may be depressed to travel through said body portion to dischargeliquid therefrom through the needle, the piston being in the form of atube having closed ends, the forward of which is provided with a closuremember which is separable from the end by engagement with said sleeve asthe piston is fully depressed to provide an aperture in the forward endthrough which the needle may pass to enter the interior of the piston asit assumes its second position.
 10. A fluid handling device having aneedle retraction assembly adapted to bring about the retraction of ahollow needle after use, said fluid handling device comprising:a hollowbody portion provided at one end thereof with an end wall having ahollow mounting portion, said mounting portion comprising an annularwall extending distally from said end wall, said mounting portionfurther including a distal wall having a needle passage therethrough; ahollow needle having a tissue penetrating end portion and being adaptedto be movable between a first position in which the tissue penetratingend portion of the needle protrudes from said needle passage of saidhollow mounting portion and a second position in which the needle iswithdrawn completely within the hollow body portion, said needle beingprovided with a collar portion of enlarged diameter at a location spacedfrom the tissue penetrating end portion thereof, and being locatedwithin said hollow mounting portion; an O-ring positioned against acircumferential shoulder on said collar portion of enlarged diameter andsaid annular wall of said mounting portion for providing a fluid sealtherebetween as well as for retaining the needle in its first positionuntil use is completed; a spring located between said distal wall ofsaid mounting portion and a distal end of said collar portion ofenlarged diameter, said spring for biasing said needle into the secondposition within said hollow body portion; and a sleeve located aroundsaid collar portion of enlarged diameter and within the hollow mountingportion of said hollow body portion, said sleeve having a distal end incontact with said O-ring, said sleeve being slidable within the mountingportion and which can be forced forwardly to dislodge the O-ring fromsaid shoulder so as to permit the needle to move automatically from itsfirst position into its second position under the influence of saidspring, further comprising a hollow piston which may be depressed totravel through the body portion to discharge liquid therefrom throughthe needle, the piston being in the form of a tube having closed ends,the forward of which is provided with a closure member which isseparable from the end by engagement with said sleeve as the piston isfully depressed to provide an aperture in the forward end through whichthe needle may pass to enter the interior of the piston as the needleassumes its second position, wherein the mounting portion is off-centerand towards a peripheral edge of the body portion, and wherein saidpiston comprises more than one closure member in the forward endthereof, said body portion and said piston having a cross-sectionpermitting assembly in more than one rotational position relative to oneanother.
 11. The syringe according to claim 10 wherein the body portionand piston are of elliptical cross section and wherein said more thanone closure member comprises two spaced closure members in the endforward of the piston.
 12. The fluid handling device according to claim10, wherein said device is a syringe, said syringe having a hollowpiston within said body portion which may be depressed to travel throughsaid body portion to discharge liquid therefrom through the needle, thepiston being in the form of a tube having closed ends, the forward ofwhich is provided with a closure member which is separable from the endby engagement with said sleeve as the piston is fully depressed toprovide an aperture in the forward end through which the needle may passto enter the interior of the piston as it assumes its second position.